1. Field of the Invention
The present invention relates to an imperfect combustion detecting device.
2. Description of the Related Art
As a conventional imperfect combustion detecting device, a kind that uses a CO sensor to detect a CO level in combustion gas, having been generated by a burner in a combustion apparatus, is known. With such imperfect combustion detecting device, a deterioration status of the CO sensor is detected. When it is determined that deterioration of the CO sensor has progressed to the extent that the normal detecting function cannot be expected in the near future, the imperfect combustion detecting device lets out a maintenance request to notify a user that the CO sensor needs to be changed (e.g. Japanese Patent Laid-Open No. H08-14556).
However, such maintenance request is not let out after the CO sensor has reached the end of its useful life at which point the normal detecting function is practically no longer available, but is let out in advance when it is determined that the CO sensor has reached the end of its predetermined “probable useful life”, while the CO sensor is still capable of performing the normal detecting operation.
Therefore, even after the maintenance request has been let out, as long as functions of the combustion apparatus other than the CO sensor is normally operating, there is a possibility that the user or service provider keeps using the combustion apparatus without changing the CO sensor.